1. Field of the Invention
The present invention relates to a friction stir welding device for welding an article to be welded by frictionally stirring the same.
2. Description of the Related Art
An article to be welded forms a joint section by butting two members to be welded. The friction stir welding device fluidizes and stirs the joint section of the article to be welded due to frictional heat by a welding tool, thereby welds the two members to be welded.
FIG. 51 is a perspective view showing a friction stir welding device 1 of the first related art. The friction stir welding device 1 of the first related art includes a friction stir welding (FSW) head 2 and a table 3. The FSW head 2 is provided with a welding tool 4 and rotates the welding tool 4 round a predetermined reference axial line L1 and also moves it along the reference axial line L1. The table 3 butts two members to be welded 5 and 6, thereby holds them as an article to be welded 9.
The table 3 includes a workpiece holding section 7 for holding the article 9, a base 8, and a table driving means (not shown). The workpiece holding section 7 is movably installed on the base 8. The table driving means moves the workpiece holding section 7 in parallel with a welding line 10 of the article 9. The FSW head 2 is fixed to the base 8 of the table 3 by a column section 12. The column section 12 is extended horizontally so as to one-sidedly support the FSW head 2.
FIGS. 52 and 53 are perspective views showing friction stir welding devices 13 and 15 of the second related art. The friction stir welding devices 13 and 15 of the second related art include a support section 16 for supporting the FSW head 2 and a head driving means 14 for driving to move the support section 16. The support section 16 supports the FSW head 2 extended horizontally one-sidedly or double-sidedly. The head driving means 14 moves the support section 16 in parallel with the welding line 10 of the article 9. For example, Japanese Patent Laid-Open Publication No. 2002-160077 discloses this kind of related art.
In the first related art aforementioned, the table driving means must convey the workpiece holding section 7 extending over the length of the welding line 10 or more. Further, in the second related art, the table driving means must convey the support section 16 over the length of the welding line 10 or more. Further, the head driving means 14 must carry the support section 16 horizontally outside the article 9.
There is a case that the article to be welded 9 is large and heavy such as a pillar panel, a hull structural member, or a railroad car panel. In this case, in the friction stir welding devices 1, 13, and 15 of the related arts, the table driving means and the head driving means are also made inevitably large. Therefore, the equipment cost and installation space are also made inevitably large. When the friction stir welding device is made large, it is necessary to ensure the positioning accuracy of the welding tool required for friction stir welding in a wide space. Further, the own weight of the device itself is made heavy due to enlargement, so that it is necessary to increase the strength of the driving means.
As mentioned above, in the related arts, when the article to be welded 9 is large, a large friction stir welding device is necessary. Thus the capital investment required for manufacture and introduction thereof is increased inevitably. Further, it is difficult for one friction stir welding device to flexibly deal with articles to be welded in different shapes.